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Flashcards in Lab 7 Deck (27):
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Bovine, lung

  1. ?
  2. ?
  3. ?
  4. ?

 

  1. Neutrophils

  2. Fibrin

  3. Interlobular lymphatics with fibrin and hemorrhage

  4. Fibrin thrombi

    In this section of lung, the interlobular septa are widely expanded by diffuse exudation and alveoli contain multifocal cellular exudate within many lobules.  Note the engorgement of alveolar capillaries with blood (hyperemia) and even hemorrhage in some areas.  The tangled fibrillar eosinophilic material in the septal areas is fibrin with intermingled neutrophils. 

 

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Bovine, lung

  • 5?
  • 6?

5- Neutrophils

6- Fibrin

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Bovine, lung

  1. Are there fibrin thrombi in septal lymphatics? 
  2. How does this affect exudation?  

  1. There are indeed fibrin thrombi. 
  2. Because lymphatics drain lymph and inflammatory fluids away, clogging them causes net accumulation of more fluid exudate and perhaps delayed resolution of the exudate. 
    • This may not be all bad in that the fibrin may also help prevent spread of the bacterial infection through the lymphatics. 
    • However, because exudate may persist longer, the inflammation may end up causing more harm than if it were speedily resolved. 
    • The organ might be injured at the risk of saving the animal.

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Histomorphologic Diagnosis:  Acute fibrinopurulent bronchopneumonia

  • Be prepared to state why each one of the components of this morphologic diagnosis was used.

  • Acute because the exudate is predominantly neutrophils and fibrin,
  • diffuse because most of the section is affected (likely locally extensive grossly),
  • fibrinopurulent because of the nature of the exudate, and
  • bronchopneumonia for inflammation of lung that also involves airways.

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Tissue from a foal that was born healthy but soon became sick, had fever, was reluctant to stand, and died 2 days later. The kidney has scattered lesions in the cortex.

  1. What are these cells and what does this imply about the duration?

  1. These are neutrophils, which suggests acute inflammation.

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Tissue from a foal that was born healthy but soon became sick, had fever, was reluctant to stand, and died 2 days later. 

Also present in many glomeruli are basophilic aggregates of small particles

  • What is 2?
  • Are these postmortem or are they important in the pathogenesis of the lesions?

  • 2- Bacterial colonies
  • These are likely antemortem bacteria because they are surrounded by an inflammatory response. 

    • Postmortem bacteria are usually large rods, but because they proliferate after death, they do not cause an inflammatory response. 

    • Dead animals can't do inflammation, DUH!

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Tissue from a foal that was born healthy but soon became sick, had fever, was reluctant to stand, and died 2 days later.

  1. The source of the bacteria is not known for certain, but it is suspected that the umbilicus was contaminated before, during, or shortly after birth and that the bacteria entered the blood.  What would you term this process?
  2. What would this disease be called?

  1. Term this bacteremia, bacteria circulating in the blood. 
    • Some people would use the term septicemia, which implies the profound disease manifested by the presence of bacteria (and their toxins) in blood. 
    • One can have bacteremia without having overt disease. 
    • Septicemia implies that a severe clinical illness is present.
  2. navel ill

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Tissue from a foal that was born healthy but soon became sick, had fever, was reluctant to stand, and died 2 days later.

  • Morphologic diagnosis?

Acute purulent glomerulonephritis with bacterial colonies

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Signalment and history: Tissue from a 10 year old Thoroughbred that presented with a displaced large colon and developed inflammation of the cecum and colon after surgery

  • Describe the lesions.

  • The mucosa of the large intestine is diffusely granular and is tan to red to brown in color. 
  • The lumen contains an aggregate of tan to red to yellow friable material that is in some places loosely adhered to the mucosa. 
  • The serosal surface of the intestine is roughened and tan to red in some regions.

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Signalment and history: Tissue from a 10 year old Thoroughbred that presented with a displaced large colon and developed inflammation of the cecum and colon after surgery

  • The luminal exudate, which consists largely of fibrin, creates a mat-like mucosal covering.  Name this film-like exudate.

Fibrinonecrotic (diphtheritic) pseudomembrane

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Signalment and history: Tissue from a 10 year old Thoroughbred that presented with a displaced large colon and developed inflammation of the cecum and colon after surgery

  1. Name the lesion

  2. What is the medical term for inflammation of the cecum and colon? 

  1. Acute fibrinonecrotic colitis.
  2. Typhlocolitis. 

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Signalment and history: Tissue from a 10 year old Thoroughbred that presented with a displaced large colon and developed inflammation of the cecum and colon after surgery

  • The image bellow shows the tissues at necropsy (fresh).  Name the serosal change/pattern.  

  • Suffusive hemorrhage – note the broad, somewhat lineal, “paint-brush” like pattern. 
  • The term purpura can also be applied, as there are disseminated petechiations and ecchymoses. 

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Signalment and history: Tissue from a 8 month old female Percheron presenting for swollen limbs and a jugular pulse.  Other changes at necropsy included a congested liver and 20L of fluid within the peritoneal cavity.  Photograph shows the tissues as they appeared at necropsy.

  • Describe the lesion.

  • Heart: The pericardial sack was thickened and its internal surface was diffusely covered by a layer of yellow, thick, fibrilar  material.
  • When pulled, this material was delicate and could be easily broken (fibrin).
  • The heart was diffusely covered by a yellow, thick, friable material (fibrin).
  • When sectioned, the heart muscle was covered first by a 2-3mm thick layer of firm, white, dense material (fibrous connective tissue) and then by a 5-10 mm thick layer of yellow-green friable material (fibrin).

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Signalment and history: Tissue from a 8 month old female Percheron presenting for swollen limbs and a jugular pulse.  Other changes at necropsy included a congested liver and 20L of fluid within the peritoneal cavity.  Photograph shows the tissues as they appeared at necropsy.

  1. Name the shaggy, friable material on the pleural surface.
  2. Name the lesion(s).

  1. fibrin.
  2. Fibrinopurulent pericarditis and epicarditis, diffuse. 

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Signalment and history: Tissue from a 8 month old female Percheron presenting for swollen limbs and a jugular pulse.  Other changes at necropsy included a congested liver and 20L of fluid within the peritoneal cavity.  Photograph shows the tissues as they appeared at necropsy.

  • As seen in the photograph, this horse’s pericardial sac was distended with 2L of yellow-tinged fluid.  Relate the cardiac lesions to the swollen limbs, hepatic and peritoneal changes. 

  • The increased pressure within the distended pericardial sac limited diastolic filling of the right ventricle (diastolic right heart failure).
  • This resulted in blood ‘backing –up’ in systemic circulation, manifesting as edema, hydroperitoneum, hepatic congestion. 

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Signalment and history:  Tissue from a 1 year old male DSH, presenting for respiratory distress

  • What is arrow pointing to?

fibrin

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Signalment and history:  Tissue from a 1 year old male DSH, presenting for respiratory distress

  • Describe the lesion(s) in the thorax. 

  • The pulmonary pleura, pericardium, mediastinum and diaphragm are covered by a shaggy, tan material 1mm thick. 
  • This material can easily be avulsed from these surfaces. 
  • Larger concretions of similar exudate (.5-2cm) can be observed in the ventral thorax. 
  • The lungs are compressed (atelectasis). 

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Signalment and history:  Tissue from a 1 year old male DSH, presenting for respiratory distress

  1. Why do the lungs appear to take up so little room in the thorax? Name this change. 

  2. Name the lesions.

  1. There was likely a large volume of exudate within the thoracic cavity, resulting in compression of the pulmonary tissues. 
    • This is called atelectasis. 
  2. Pyothorax with fibrinopurulent pleuritis and atelectasis.  

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Signalment and history: Tissue from a 1 year old calf that presented for prolonged respiratory distress.

  1. What is this?
  2. ?

  1. Arytenoid folds-multifocal fibrinonecrotic laryngitis

  2. Rounded edges and granulation tissue

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Signalment and history: Tissue from a 1 year old calf that presented for prolonged respiratory distress.

  • Describe the lesion(s)

  • There are multifocal (bilaterally symmetrical) ulcerations on the opposing surfaces of the arytenoid folds of the larynx. 
  • These regions are approximately 2-3 cm in diameter and are covered by a thick layer of tan to yellow friable loosely adhered material (granulation tissue and fibrin). 
  • Surrounding laryngeal tissues are moderately to markedly thickened (probably due to inflammation and edema). 
  • The generalized redness of the specimen on the left is most likely due to post-mortem change.

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Signalment and history: Tissue from a 1 year old calf that presented for prolonged respiratory distress.

  • Name the lesion(s). 

  • The lesion is necrotizing (or ulcerative) and fibrinous laryngitis.  

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Signalment and history: Tissue from a 1 year old calf that presented for prolonged respiratory distress.

  1. What is the substance on the surface?  
  2. How did it get there?

  1. There is ulceration of the mucosa of the arytenoid folds of the larynx that is covered by a layer of granulation tissue (firmer) and then fibrin (loosely adhered, tan to yellow material).
  2. Vascular damage allows fibrinogen to leak out into interstitium where thrombin converts it to a fibrin monomer. 
    • The fibrin monomers form a polymer which are cross-linked and stabilized via activated Factor XIIIa.

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Signalment and history: This is tissue from a 9 year old female Labrador Retriever dog which presented lethargic and reluctant to move. Clinical evaluation revealed hypothermia and hypotension.

  1. ?
  2. ?

  1. Sacculations in uterine horn (cornua)
  2. Purulent exudate in lumen

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Signalment and history: This is tissue from a 9 year old female Labrador Retriever dog which presented lethargic and reluctant to move. Clinical evaluation revealed hypothermia and hypotension.

  • Describe the lesion 

  • Bilaterally, the wall of the cornual uterus is diffusely thickened to approximately 3 mm in width and forms sacculations up to 5cm in diameter along the length of each horn.
  • The lumen of the uterus in diffusely filled with light brown homogenous purulent and exudate (a sample of the content was in a syringe).  
  • The exudate has a pungent and unpleasant smell.
  • The mucosal surface is irregularly thickened, rough and reddened.

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Signalment and history: This is tissue from a 9 year old female Labrador Retriever dog which presented lethargic and reluctant to move. Clinical evaluation revealed hypothermia and hypotension.

  • provide a possible pathogenesis

  1. Pyometra is usually a suppurative bacterial infection of the uterus that occurs in older female dogs during diestrus (the progesterone-dominated phase of the ovarian cycle). 
  2. Progesterone causes increased endometrial growth and glandular secretion, continued closure of cervix, and decreased migration of neutrophils to the uterus and reduced phagocytosis of uterine bacteria. 
  3. Acute bacterial infection of the progesterone-primed uterus attracts neutrophils to the uterine lumen, resulting in pyometra. 

FYI= Pyometra often occurs as a sequela to endometritis or metritis.  The bacterium most commonly present in pyometra in the bitch is E. coli.  Sepsis is common. The closure of the cervix is not always complete, and some discharge occurs.  

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